Water traversing air cushion vehicle



WATER TRAVERSING AIR CUSHION VEHICLE Melville W. Beardsley, SevemaP'ark, Mil.,4 asslgnor, hyv

mesne assignments, to National Research Associates,A int-., Laur'ch Md., a corporation 'of Maryland Filed Feb. 28,4 1961, SenNo. 99,006 v ll' Claims. (Cl. 11k-61) .The present invention relates to. an air cushion vehicle -vespecially adapted'to travel over water, and has particular reference to 'an improved type of air cushion vehicle for use over water and certain types of terrain, particularly I Accordingly, the present invention is directed toa craft that can travel conveniently over deep or shallow water, in weed lled waters,'and can also pass over mud banks,

j wet sand, and even dry surfaces which are relatively smooth.

The present invention is also'commercially attractive in ICC ber or .plastic section which is merely an extension ,ofv

' l deck 12. .In the picture of the vehicle in FIG. l thel flexi-A shown in this ligure by arrows which designate vthe ow that-terrain that mightv be,w found adjacent' to bodies of that it can eliminate the use of expensive docking facili- Vties through its ability to pass onto and over flat dry surfaces. v

In the new type vehicle of this invention there is no draft required thus providing advantagesof decreased `resistance or dragl as compared with boats of conventional or hydrofoil design.

Als`o,. the vehicle of this invention will not 'encounter the vdifficulties .inherent with 4propellerson conventional boats such as damage sustained 'by striking obstacles or 4debris in the water and 'weedfouling Furthermore, the vehicle of the present invention through the use of thenovel mechanical design disclosed allows the building ofa lighter structure and the obtainin of higher speed with the' use of iesspower.

Basically, the present invention provides a novel and improved vehicle which can ride over the surface of water with a minimum of surface friction and wave drag.

rlfhese as well as further advantages which are inherent in the invention will become apparent fromthe following description, reference being had to the accompanying drawings, wherein? L FIG. l is a perspective view of anembodiment of the vehicle of this invention;`

FIG. 2 is a partially cut away sidel elevation view of the vehicle of the present invention, sectioned as seen substantially on line 2- 2 of FIG. 3;

` FIG. 3 isa Atop plan view of the vehicle;

, FIG. 4 is a rear elevation view;

FIG. 5 is a front elevation view;

FIG. 6 isa perspective partial bottom view of one of the runners showing detail.

With particular reference now to the figures, there is illustrated a mechanical embodiment of the features of the present invention wherein FIG..1 is a perspective view of an air cushion vehicle which may be used primarily for 10 vbut belowthe deck 12. In the rear of hull 10 other y fans 13 of ailarger variety than fans 1 1 are alsok placed.

below the. deck The-bow ofv hull 1 0'is composed'of a` 'flexible sheet-material `14 supported bya heavy foam rubble material 14 is shown as it would appear when inflated by air :from .fans 11. The -relationship of'the fans and the llexible bow to the rest of hull 10 vis also depicted in the top -plan view designated as FIG.l 3.

FIG. 2 is a partial cut away view of the vehicle of this invention showing the internal vstructure of hull l0. As

of air fan 1l takes in airthrough ports 2l and blows this air into the tunnel plenum 19 ,under hull 10. Some of this air takes the path toward ythe forward part of hull lil` and lpassesthrough flexible material 22 havinglholestherethrough. This air passing through flexible material 22 enters an air chamber behind the flexible bow'14 and in I tlates it to a rounded shape allowing it to act asa cushion. against shock caused by impact `of the water which may occur during the forward motion of the vehicle in rough water. The heavy layer of foam rubber 15 which is the extension of deck 12 allows this bow 14, to deflect under impact and yet to keep its shape even when no air is pumped into this section.

Some of the air from fans 11 enters'an opening at the forward end ofcondnit 23 and passes through this conduit to inflatable-structure tlaps 24 located toward the rear of the vehicle. The amount of air entering the intl'atablef structure tlaps 24 is controlled by valve 25 in conduit 23` 4which is under the control of the operator of the vehicle. Inflatable llaps. 24 have an escape outlet 26 as shown in FIG. 2 making it possible to vary the pressure in flaps 24 i by varying the relationship of the flow area through valve 25 to the llow area of 'the escapeoutlet 26.

Fans 13 in the rear of the vehicle draw in a large voiume of air and pass some of this air out under the rear-0f hull 10 and a portion out between-louvres 27 located in the rear as shown, when these louvres are in an open position.

The sides of hull 10 extend downward in the form of skegs or runners 41 and v42, fixed at the bottom of hull 10 and running longitudinally and enclosing the sides of the plenum beneath hull l0 as depicted in FIGS. 4 and 5. An additional runner 43 is located under the hull running longitudinally along the center of the bottom. Although. runner 43 is depicted here as a solid section, with air beingvpiped to the inflatable flaps 24 through a conduit 23, an-

other embodiment not shown would allow the air to -pass foils 51, shown in this example only on the inside surface of the runners 41 and 42 maybe located with like effect on the outside surface of these runners or other longitu-l dinal positions on the lower sections of the runners where;

by the 'hydrofoils may improve longitudinal stability in sides of that runner andv also jin vthe forward section of j the vehicle.

3,140,687 PstentedvJuiy 14, '1964? I ally rearward direction so that some thrust is derived from the escaping air. This series of planing surfaces 61 is only found on side runners 41 and 42, since it would have no effect if used on center runner 43.

In operation, the forward fans 11 are used basically to provide the plenum beneath hull with air having a p positive static pressure which, acting upward on the under surface of hull 1.0, provides a force which lifts the vehicle clear of the surface over which it travels. lAs stated before the air from fans 11 also provides for the inflation of flexible bow 1 4 for a cushioning effect. Under desired operating conditions some of the air from these fans escapes out under runners 41 and 42 through the open rareas between the planing surfaces 61 and the water or ground surface beneath them. The remainder is discharged rearward through the opening between the bottom of inflatable flaps 24 and the surface over which the vehicle is traveling. Control of this open area determines the pressure under the vehicle and the'height at which it operates and the amount of thrust developed.

Inflatable flaps 24 which are also supplied with air from fans 11 are used to accomplish trim control for the occasions where the vehicle is carrying a laterally off-center load. The supply of air to these flaps is individually controlled by valves 25. The vinflation of each flap is controlled to provide the desired amount of open area for the discharge of air from under each side of hull 10 so as to cause any desired pressure difference to compensate for laterally offcenter loads.

The propulsion for this vehicle is provided mainly by the larger fans 13 which are located at the rear vof the hull and usually designed to handle a greater air flow than forward fans 11. Through control of the discharge flow from these fans the pitch and trim of the vehicle may be changed where desired and the speed may be further controlled. The discharge flow area and direction may be controlled by the louvres 27 in the rear of the vehicle which may be opened or closed as desired. When a minimum nose down pitch moment is desired, louvres 27 are moved to their open position thereby allowing free airflow out of the hull from the rear fans with a large horizontal component of velocity. -eAs the louvres are moved to a closed position, there is an increasing nose down pitching moment imparted to the hull 10 due to the downward discharge of the air flow and the buildup of pressure beneath fans 13 and the rear of hull 10. It is possible to develop sufficient pressure with these rearward located fans to provide lift for the entire vehicle, a1- though in the embodiment shown, the lift pressure is supplied by air from front located fans.

A center skeg 43 is incorporated to divide the air space under the hull into two longitudinal parts to provide lateral stability. If one side is depressed from an equilibrium condition the air escape area at the rear, under inilated flap 24, and along the side under planing surfaces 61, isreduced so that the pressure under the low side is increased to provide a correcting moment. Lateral stability is further enhanced by the planing or hydrofoil surfaces 51, since the surface 51 on the low side is immersed deeperthan the surface 51 on the high side and thus produces more lift to produce a corrective moment.

The vehicle is steered by rudders 44 and 45, located at the rear of runners 42 and 41, respectively. These rudders have a generally trapezoidial shape and are hinged at their forward edge. Due to the shape and the manner in which they are attached to the respective runners, there is no portion of the rudder below the bottom surface of the runner when the rudder is in a straight back position.

' This enables the vehicle to travel over a smooth hard surface without a scraping of the rudder. Since the hinged edge slants forward and upward, it will be noted that as the rudder is turned its trailing edge moves to an increasingly lower level causing greater effectiveness due to the larger area in contact with the water. The upper inner surface of rudders 44 and 45, being in contact with the discharged air flow, also provides turning moment due to the deflection of this air flow.

A preferred embodiment of the invention has been described above. Various changes and modifications, however, may be made within the scope of theyinvention as set forth in the appended claims. Accordingly, reference should be made to these claims in determining the full scope of the invention.

What is claimed is:

l. An air cushion vehicle for travel primarily over water comprising a hull having a horizontal bottom, longitudinal vertical wall members extending downwardly from the sides and below the horizontal bottom of said hull, a first means for blowing air under the generally forward part of said hull, a second means for blowing air under the generally rear part of said hull, an inflatable lateral member extending downwardly below the horizontal bottom of said hull and between said longitudinal wall members, and substantially downwardly opening exhaust means in said inflatable member for controlling the air pressure therein thereby controlling the height of the lower edge of said lateral member.

2. An air cushion vehicle for travel primarily over water comprising a hull, a plurality of wall members located longitudinally along the bottom of said hull, one of said wall members located along the port side of the bottom of said hull and another of said wall members located along the starboard side of the bottom of said hull, at least one inflatable structure located under said hull, one said inflatable structure located transversely in the space between a pair of said wall members, means to supply air to said inflatable structure, and valve means to control the amount of air supplied to each of said structures, each of said inflatable structures having an exhaust means through which some of the air supply continually leaves said structure.

3. An air cushion vehicle for travel primarily over water comprising a hull, a plurality of wall members lo cated longitudinally along the bottom of said hull, a first means for blowing air under the generally forward part of said hull, a second means for blowing air under the generally rear area of said hull, and rudder means for steering said hull when over water attached to the rear end of a longitudinal wall member and shaped generally in the form of a trapezoid, said rudder having a sloping hinge line along the forward edge of said rudder with the top of s aid hinge line in a forward position in relation to the bottom of said hinge line whereby turning of said rudder moves part of said rudder below the surface plane upon which said wall members travel and with said rudder in a straight back position all parts of said rudder are above the surface plane upon which said wall members travel thereby allowing for travel over a hard surface.

4. An air cushion vehicle for travel primarily over water comprising a hull, a plurality of vertical wall members located longitudinally along the bottom of said hull, one of said vertical wall members located along the port side of the bottom of said hull and another of said vertical wall members located along the starboard side of the bottom of said hull, a rst means for blowing air under the generally forward part of said hull, a second means for blowing air under the generally rear area of said hull, at least one inflatable structure located under said hull, one said inflatable structure located transversely in the space between a pair of said vertical wall members, means to supply air to said inflatable structure, valve means to control the amount of air supplied to said inflatable structure, said inflatable structure having an exhaust means near its bottom through which some of the air supply continually leaves said structure.

5. An air cushion vehicle for travel primarily over water comprising ,a hull, a plurality ofv generally vertical wall members located longitudinally along the bottom of said' hull, one of said wall members located along the port side of the bottom of said hull and another of said wall `members located along vthe starboard side of the bottom 'l vof said hull, a lirstmeans for blowing 'air under the gen-v erally forwardpart of said hull, a second means for blowl' ing air under the 'generally rear area of said hull, at least `onefinflatable structure located under said hull, one said 'L inatable structure located transversely in thev space ber.

tween a pair of`said wall members, `means'to supply air to said inflatable structure, said inflatable structures lhavof pitch of said hull and forward motion may be obtained.

6.'An air cushion vehicle for travel" primarily over water comprising a hull, a plurality of runners located longitudinally along the -bottom of said hull, one of said vrunners located along the port side of the bottom of said hull and another of said runners located along the starair may pass out through the recessed portions of the saw# tooth shaped surface in a generally rearward direction.

- 9. An air cushion vehicle for travel primarilyover `water comprising a hull, a plurality of vertical Wall mem-f' bers located longitudinally along the bottom of said hull,

means for blowing air under said hull, a flexible bow secboard side of the bottom of said hull, a first means for blowing air under the generally forward part of said hull, a second means for blowing airunderv the generally rear area of said hull, atleast one inflatable'structure located under said hull, one said inflatable Astructure located transversely in the space betweenr a pair of saidrunners, means-to supply air to said inflatable structure, said inatable structure having an exhaust means through which some of the air supply continually leaves said structure, rudder means for steering said hull attached tothe rear end of a runner and generally in the form of a trapezoid, said rudder having a sloping hinge line along the forward edge of said rudder withfthe top of said hinge line in a forward position in relation to the bottom of said hinge line whereby turning of said rudder moves part of said rudder below the surface plane upon which said runners travel and with said rudder in a-straight back positionl .all parts of said rudder are above thefsurfaceplane upon which said runners travel thereby allowing for `travel over ahard surface.

7.-An air cushion vehicle for travel vprimarily over water comprising a hull, a plurality-of vertical wall members located'longitudinally along the bottom of said hull, one ofl saidl wall members located yalong'the port side of the bottom of said hull and another of said wall members located along the starboard side of the bottom of said hull, a first means for blowing air under the generally forward part ofv said hull, a second meansv forrblowing air' under the generally rear area of said hull, at least one inllatable structure located under said hull,yone said inflatable structure' located tran'sverselylin the space between a pair of said'wall members, means to supply airto said inflatable structure, said inatable structure having an exhaust means near its bottom through which some of the air supply continually leavesA said structure, and planing surfaces located in a substantially horizontal plane .I and yattached to said wall members'in a generally perpendicularv direction to said `Wall members. c

8. An air .cushion vehicle fortravel primar-ily over water comprising a hull having av plenum chamber therein with vertical longitudinal and transverse walls, at least `one of said wallsbeing flexible, means for blowing air into said plenum chamber, one of -said vertical longitudinal wall members located along the port'side of the bottom of said hull and another of said vertical longitudinal wall members located along the starboard side of the bottom of said hull,'said pair-of vertical wall members located in a longitudinal direction along the starboard f and port'bottom edges of saidhullhaving afgenerally sawtootli shape on their bottom surfaces. said sawtooth shaped bottom surface having the outside lof the lower portion of the tooth edge aft of the inner portion whereby .ingth'e bow of said hull, and a lflexible ele tion attachedl to the forward part of said'hull and formtion of said hull and thereby form a bow having a c'ushioning effect against impact of forces hitting against said hull during forward motion of said hull. 10. An air cushion vehicle for travel primarily over water with directional controls comprising a detiectable member in the rear of the vehicle in the path of air flow of the air cushion vehicle with a lower rear extremity `which descends as it is horizontally deflected,v` said deflectable member having a sloping hinge line along the fot'- ward edge of said member with the top of said hinge line in a forward position in relation to the bottom'of said hinge line.

1l. An air cushion vehicle for travel primarily over water comprising a hull, a plurality of vertical 'wall members located longitudinally along the bottom of said hull, one of said vertical wall members located along the port side of the bottom of said hull and another of said vertical wall members located along the starboard side of the bot-v tom of said hull, said pair of vertical wall members located in a longitudinal direction along the starboard and port bottom edges of said hull having-a generally sawtooth shape on their bottom surfaces, said sawtooth shaped bottom surface having the outside of the lower portion of the tooth edge aft of the inner portion whereby air may pass .out through the recessed portions of the sawtooth shaped surface in a generally rearward direction, a first means for blowing air under the generally forward part of said hull, a second means for blowing air under the generally rear area `ofy said hull, at least one inflatable flap located under said hull', one said intiatable ap located transversely in the space between a pair of said vertical wall members, means to supply air to said inatable ap, valvemeans to control the amount ofV air supplied to said flap, said inflatable ap having an exhaust means through which some of the air supply continually leavessaid flap, louvres mounted in the rear of said hull opening toward the rear of said hll whereby additional control of pitch of said hull'and for ward motion may be obtained, rudder means for steering said hull `attached to therear end of averticalwall member and lshaped generally in the form, of a trapezoid, said rudder having a sloping hinge line along the forward edge of said rudder with the top of said hinge line in a forward position in relation to the bottom of said hinge line whereby turningof said rudder moves part of said rudderv below the surface plane upon which said vertical wall members travelv and with said rudder. in a straight b ack position all parts of said rudder are above the surface-plane upon which said vertical wall members travel thereby References Cited inthe file of this patent UNITED STATES PATENTS 932,733 Weyher f n Aug. 31'; 1909 1,081,489 Currie f Dec. 16, 1913 1,294,081 Gasiorowski Feb. 1I, 1919 (Other references on following page) l Y 7 UNITED STATES I PATENTS v Lake June 17, 1919 Dunajeff Apr. 18, 1922 n Royer May ,7, 1929 Haase Oct. 15, 1929 lKloen July 21, 1931 Warner Aug. 18, 1931 Alexander Nov. 23, 1932 Parker Nov. 7, 1933 Leray Ian. l, 1935 rSanden June 18, 1935 l 8 Crstadoro June 29, 1943A Persson Aug. 22, 1944 Coates Mar. 20, 1962 Priest Apr. 3, 1962 Hurley Dec. 4, 1962 FOREIGN PATENTS Great Britain of 1908 France Apr. -3, 1908 France July 4, 1949 France June 25, 1956 Sweden Apr. 1l, 1944 

1. AN AIR CUSHION VEHICLE FOR TRAVEL PRIMARILY OVER WATER COMPRISING A HULL HAVING A HORIZONTAL BOTTOM, LONGITUDINAL VERTICAL WALL MEMBERS EXTENDING DOWNWARDLY FROM THE SIDES AND BELOW THE HORIZONTAL BOTTOM OF SAID HULL, A FIRST MEANS FOR BLOWING AIR UNDER THE GENERALLY FORWARD PART OF SAID HULL, A SECOND MEANS FOR BLOWING AIR UNDER THE GENERALLY REAR PART OF SAID HULL, AN INFLATABLE LATERAL MEMBER EXTENDING DOWNWARDLY BELOW THE HORIZONTAL BOT- 